Portable cellular telephone with automatically transmitted origination message and method therefor

ABSTRACT

A radiotelephone ( 10 ) simulates the call origination process performed by land-line telephones. Dial tone is generated ( 78 ) in response to an off-hook condition and removed when a first digit ( 54 ) is dialed. A timer process ( 84, 110 ) and a number analysis process ( 100 ) simultaneously evaluate dialed digits to detect the completion of dialing. The number analysis process ( 100 ) identifies seven, ten, and eleven digit, and indeterminate length phone number formats ( 64, 66, 52, 68 ). The ten digit format is recognized in response to remotely programmed ( 42 ) connected NPA codes. For most calls, the number analysis process ( 100 ) instantly detects a phone number&#39;s final digit ( 62 ). In a few cases the timer process ( 84, 110 ) detects the final digit through the absence of dialing activity for a predetermined duration. When the final digit ( 62 ) is detected, an origination message is transmitted to a cellular network.

RELATED PATENTS

The present invention is a continuation of “Cellular Radiotelephone WithDialed Number Analysis,” Ser. No. 08/642,237, filed May 2, 1996, andissued as U.S. Pat. No. 6,021,335, which is a continuation of “CellularRadiotelephone With Dialed Number Analysis,” Ser. No. 08/315,014, filedSep. 29, 1994, and issued as U.S. Pat. No. 5,535,260, which is acontinuation-in-part of “Multiple Mode Personal Wireless CommunicationsSystem,” Ser. No. 08/201,445 filed Feb. 24, 1994, and issued as U.S.Pat. No. 5,594,782.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to cellular radiotelephones.More specifically, the present invention relates to the origination ofcalls from cellular radiotelephones.

BACKGROUND OF THE INVENTION

The telephony industry has long used certain standards in managing theprocesses which occur when land-line telephones are used to makeout-going calls. Generally, when a telephone goes off-hook, a circuit isestablished between the telephone and a central office. The centraloffice typically includes complex, sophisticated, and expensiveequipment which provide the intelligence to manage the call originationprocess. The central office applies dial tone to the telephone's localloop as soon as the off-hook condition is detected. Dial tone providesaudible feedback which informs the user that the system is waiting forthe user's input. After a first digit is dialed, the central officeremoves the dial tone.

As the user continues to dial digits, the central office analyzes thedigits in order to determine routing and call charges and to identifywhen an entire phone number has been dialed. This analysis is a complextask because a wide variety of call types may be originated at thetelephone. For example, local calls, non-toll inter NPA calls, tollcalls, operator assisted calls, international calls, and other types ofcalls must be distinguished from one another, and the different types ofcalls may require the dialing of different lengths of digit streams. Inareas where central offices in different area codes or LATAs reside nearone another, hundreds of central office codes must be distinguished fromhundreds of other central office codes. Moreover, these complex rulesfor dialed number analysis differ from central office to central officeso that each central office essentially implements its own unique numberanalysis plan.

Cellular telephony has adopted a slightly different technique fororiginating calls. Generally, a user manipulates a handset to storedialed digits in a digit buffer memory located at a cellularradiotelephone. When the user has entered a complete number in the digitbuffer, the user presses a “send” key, which signals a conventionalradiotelephone to send an origination message to the network. Thenetwork then analyzes the digits in a manner similar to that done forland-line telephones. This technique conserves the RF spectrum becausethe network does not allocate the scarce resource of an RF channel tothe radiotelephone at the instant an off-hook condition occurs, butwaits until after the user presses the send key.

On the other hand, the conventional cellular telephony call originationtechnique causes several problems. For example, this technique isdifferent from the widely understood and ubiquitous land-line telephonycall origination process. The difference causes numerous complications.New cellular customers must be taught a call origination process that isdifferent from one with which they are usually familiar, and a largecost is associated with teaching a new process to an entire populationof users. For many users, the use of a different call originationprocess causes confusion, which ultimately leads to dissatisfaction. Noaudible feedback, such as the well known dial tone, is provided to letusers know that their instrument is awaiting user input, and many userswho are accustomed to the land-line telephony call origination processoften become distracted by the lack of this feedback. In addition, thecellular call origination process requires the extra step of pressingthe send key. This extra step seems unnatural and is easily forgotten bynew users who are accustomed to the land-line telephony call originationprocess.

Various prior art cellular telephony devices have attempted to make thecellular call origination process more closely resemble thecorresponding land-line process. For example, a few prior art cellulardevices have generated a dial tone at the radiotelephone itself toprovide the familiar feedback. However, these devices have beenencumbered by additional switches and related mechanisms that establishon-hook and off-hook conditions and that generally limit the devices'portability and flexibility.

In addition, various prior art cellular telephony devices have attemptedto detect when a user completes the dialing activity so that the devicemay then automatically send an origination message to the cellularnetwork without requiring a user to press a send key. These prior artcellular devices usually wait until no additional key presses aredetected at a keypad for a predetermined duration before automaticallysending the origination message to the network. Unfortunately, for thistechnique to be reliable the waiting duration needs to be around threeto eight seconds, which is an undesirably long and annoying wait toimpose upon users.

Still other devices have attempted to interface between land-linetelephone devices and conventional cellular radiotelephones. Suchdevices have attempted to simulate the operation of a central officeinsofar as supplying conventional central-office signals to theland-line telephone devices and in evaluating land-line telephone touchtone/rotary dial type signals to determine when a last digit has beendialed. However, such devices are hard-wired or otherwise permanentlyprogrammed to simulate a particular's central office's local dialingplan, have only a limited ability to automatically detect the completionof dialing, and are intended only for stationary use at a locationcovered by the central office whose local dialing plan is beingsimulated.

SUMMARY OF THE INVENTION

Accordingly, it is an advantage of the present invention that animproved cellular radiotelephone accommodates a call origination processthat more closely approximates the land-line call origination process.

Another advantage of the present invention is that a cellularradiotelephone is provided which analyzes digits dialed at theradiotelephone to rapidly determine when a user completes the dialingactivity.

Another advantage is that the present invention provides a dial tone foraudible feedback and quickly detects the completion of the dialingactivity for a vast majority of outgoing calls.

Another advantage is that the present invention may be configured as amobile or portable unit which may be used in any location, may bemanufactured, inventoried, and distributed without any particulararea-of-use distinction, and performs a dialed number completionanalysis process which is particularly pertinent to one particular areaof use while simultaneously performing another dialed number completionprocess which applies in any area.

The above and other advantages of the present invention are carried outin one form by a method of operating a cellular radiotelephone tooriginate a call. The method calls for identifying the entry of earlierand later dialed digits where the earlier digit is dialed before thelater digit. In response to the earlier digit, the method determineswhether the later digit is a final digit of a phone number. When thelater digit is the final digit of the phone number, an originationmessage is automatically transmitted from the radiotelephone. Theorigination message conveys the phone number to a cellulartelecommunication network.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the Figures, wherein like reference numbers refer tosimilar items throughout the Figures, and:

FIG. 1 shows a front view of a portable radiotelephone handset, whichrepresents one of various types of cellular radiotelephones in which thepresent invention may be implemented;

FIG. 2 shows a block diagram of the handset's electronic hardware;

FIG. 3 shows a flow chart of a remote programming session processperformed by the handset;

FIG. 4 shows a schematic representation of a geographical area for whichthe handset may perform a number analysis process;

FIG. 5 shows a format diagram of various digit streams which the handsetmay analyze;

FIG. 6 shows a flow chart of an idle procedure performed by the handset;and

FIG. 7 shows a flow chart of the number analysis process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a front view of a portable radiotelephone handset 10, whichrepresents one of various types of cellular radiotelephones in which thepresent invention may be implemented. While the present invention may beimplemented in any type of radiotelephone, its advantages may beparticularly beneficial in connection with portable and mobileradiotelephones. Handset 10 includes an antenna 12, auter case 13speaker 14, microphone 16, display 18, and keypad 20. With the exceptionof keypad 20, these items are conventionally found in cellular telephonyhandsets. Keypad 20 includes many of the usual numeric keys 22 andnon-numeric keys 23 conventionally found in cellular telephony handsets.However, keypad 20 omits a “send” key.

Instead of a send key, handset 10 includes a “phone” key 24 and an “endphone” key 26. Phone key 24 initiates dial tone for making calls, may bepressed to receive calls, and may be used to activate a flash hooksignal for services such as call waiting. Thus, phone key 24 conveys an“off-hook” instruction to handset 10. End phone key 26 is used to endcalls, and thus conveys an “on-hook” instruction to handset 10. Thoseskilled in the art will appreciate that the terms on-hook and off-hookhave a historical significance in connection with land-line telephonysystems that may not precisely describe cellular telephony operation.Nevertheless, for purposes of the present invention an off-hook functionor condition generally means that a user desires to use handset 10 andthe communication services provided thereby, and an on-hook function orcondition generally means that a user desires to cease using handset 10and the services provided thereby.

FIG. 2 shows a block diagram of electronic hardware included in handset10. Antenna 12 of handset 10 couples to a first port of a duplexer 28,while a second port of duplexer 28 is adapted to receive a modulated RFsignal provided by a transmitter 30 and a third port of duplexer 28provides a received RF signal to an input of a receiver 32. An outputfrom receiver 32 couples to speaker 14, and an input of transmitter 30couples to microphone 16.

A controller 34 controls the operation of handset 10. Controller 34 maybe implemented using one or more commercially available microprocessors.Controller 34 provides controlling signals to transmitter 30 and toreceiver 32. In the preferred embodiment, these controlling signalsenable/disable, and they identify frequency channels to whichtransmitter 30 and receiver 32 are instructed to tune. In alternateembodiments, the channel instructions may additionally or alternativelyconvey TDMA timing slots and/or CDMA spreading codes. In addition, thesecontrolling signals identify audio channels from which signals are to bereceived at transmitter 30 and at receiver 32.

A dual tone multifrequency (DTMF) tone generator 36 has a control inputadapted to receive controlling signals provided by controller 34. Anaudio output of DTMF tone generator 36 couples to audio inputs oftransmitter 30 and of receiver 32. Thus, controller 34 may instructtransmitter 30 to transmit DTMF tones or audio from microphone 16, andcontroller 34 may instruct receiver 32 to drive speaker 14 usingreceived signals or DTMF tones. Of course, handset 10 may also transmitand receive data, such as a 10 Kbit Manchester code which isconventionally used in cellular networks that follow an AMPs standard.

Display 18 couples to controller 34 and visually shows informationprovided thereto by controller 34. Keypad 20 couples to controller 34 sothat controller 34 may detect key presses and then appropriately respondto the key presses. A memory 38 couples to controller 34. Memory 38includes both volatile and non-volatile storage. Memory 38 stores data,variables, tables, lists, and databases that are used in connection withthe operation of handset 10. In addition, memory 38 stores programminginstructions which are executed by controller 34 and define the variousprocesses, procedures, routines, tasks, and the like performed bycontroller 34 and handset 10. A timer 40 couples to controller 34 andhelps controller 34 monitor the passage of time. While FIG. 2 showsmemory 38 and timer 40 as being separate components from controller 34,those skilled in the art will appreciate that in some applicationsmemory and timing components may be included within controller 34, andthat in other applications the timing functions may be performed throughthe execution of software programing instructions.

FIG. 3 shows a flow chart of a remote programming session process 42performed by handset 10. Process 42 is performed during a remoteprogramming session. The particular events which lead to the performanceof remote programming session 42 are not critical to the presentinvention. Such events may, for example, result from handset 10receiving a call or otherwise establishing a data communication linkwith a cellular network or through the cellular network to anotherdevice which also couples to the cellular network or a public switchedtelecommunications network (PSTN) to which the cellular network couples.Alternatively, a remote programming session may be established whenhandset 10 places a call through a cellular network to some phone numberor otherwise establishes a data communication path. After a remoteprogramming session call or other data communication path is establishedinto or through the cellular network, a remote programming session maythen begin.

Generally, data may be passed to handset 10 through the datacommunication path. As indicated in a task 44, handset 10 receives oneor more “connected” numbering plan area (NPA) codes from the cellularnetwork. The connected NPA codes have a relationship or connection,which is discussed below in more detail, to the area code or codesbelonging to the handset's home system. After receiving the connectedNPA codes, a optional task 45 is performed to receive other programmingwhich may be relevant to dialing analysis. Such programming may, butneed not, indicate whether handset 10 is configured to operate through aPBX and must therefore recognize access codes, and/or programminginstructions that define unusual or revised local dialing rules ineffect for a particular situation. After task 45, a task 46 stores thecodes and any other programming data in memory 38 (see FIG. 2) for lateruse in connection with a number analysis process, which is discussedbelow. After task 46, session 42 may receive and transfer any other dataas may be advantageous for the session, and program control eventuallycauses session 42 to end, as indicated by exit 48.

Through remote programming session 42, handset 10 may obtain programmingthat is specifically designed for particular local dialing rules. Remoteprogramming session 42 may be performed at initial activation, whenlocal dialing rules change, or when a user moves his or her service to anew location. In addition, remote programming session 42 may performedat any location. Thus, such programming may be accomplished withoutrequiring a user to visit a service center and without requiring servicerepresentatives to visit any particular place of use. Entire populationsof handsets 10 may all be reprogrammed, as may become necessary whenlocal dialing rules change, at minimal cost.

FIGS. 4 and 5 illustrate the significance of connected NPA codes. FIG. 4shows a schematic representation of a geographical area for whichhandset 10 may perform the number analysis process. FIG. 5 shows formatdiagrams of various digit streams which handset 10 may analyze. FIG. 4depicts three geographical NPA areas, labeled NPA1, NPA2, and NPA3.Generally, areas NPA1-NPA3 illustrate three distinct but contiguousareas for which three different area codes are used. A home systemcoverage area 50 is juxtaposed over one or more of the NPA areas, suchas areas NPA2 and NPA3. Area 50 represents the area within which handset10 is authorized to operate. Within area 50, handset 10 may operate onits “home” system. Outside of area 50, handset 10 will be “roaming”.Home systems and roaming are well known concepts in the art of cellulartelephony.

FIG. 5 illustrates a diverse assortment of formats for phone numbers.FIG. 5 shows earlier dialed digits to the left of later dialed digits. Aformat 52 represents a typical long distance format. Format 52 includes11 digits, where a first digit 54 is either a zero or a one, a seconddigit 56 is a first digit of an NPA code, a third digit 58 is a seconddigit of an NPA code, and a fourth digit 60 is a third digit of an NPAcode. The next three digits represent an NXX central office code, andthe following four digits represent an XXXX station code. The eleventhdigit is a final digit 62 for the phone number.

In accordance with conventional telephony terminology, the letter “N” ofthe NXX code may have any value in the range of 2-9 and the letter “X”of the NXX and XXXX codes may have any value in the range of 0-9. TheNPA code maybe either an N-0/1-X code or an NXX code. In other words thefirst digit of the NPA code has a value in the range of 2-9, the lastdigit of the NPA code has a value in the range of 0-9, and the middledigit may be restricted to being a 0 or 1 in accordance with a currentstandard or may be any value in the range of 0-9 in accordance with anupcoming standard.

A format 63 illustrates a three digit phone number which whose secondand third digits are both ones. This format includes the ubiquitous 911emergency number. Final digit 62 is the third digit.

Format 64 illustrates a seven digit phone number which is used formaking a local, non-toll call. The first three digits 54, 56, and 58represent the NXX central office code, and the following four digitsrepresent the XXXX station code. Final digit 62 is the seventh digit.

In a format 66, the tenth digit is final digit 62.

Format 66 uses NPA, NXX, and XXXX codes without the preceding 0/1 thatformat 52 uses. Format 66 is used to different degrees in differentgeographical areas. Typically, format 66 is used to make non-toll callsbetween two different NPA areas. Whether inter NPA calls are to beconsidered toll calls is a private arrangement of the party or partieswho provide services in the two NPA areas. The preceding zero or one isoften omitted so that customers clearly understand that such a call isnot a toll call. This ten digit format applies to connected NPA codes.In other words, inter NPA calls between connected NPA areas use tendigit dialing while inter NPA calls between non-connected NPA areas useeleven digit dialing.

Format 68 illustrates variable length phone numbers for which theprecise placement of final digit 62 is indeterminate. Generally, format68 numbers have either a zero or one in first digit 54 and either a zeroor one in second digit 56. Such numbers correspond to internationalcalls, special signalling codes that address long distance operators,and the like.

Referring back to FIG. 4, if, for example, NPA1 and NPA2 are connected,then one may place a call from NPA2 to NPA1 using ten digit dialing, asshown in format 66 (see FIG. 5). If not connected, then one may place acall from NPA2 to NPA1 using eleven digit dialing, as shown in format 52(see FIG. 5). Whether to use ten or eleven digit dialing depends uponthe particular dialing arrangements made in the particular area wherehome system 50 is located.

However, through remote programming session 42 (see FIG. 3) handset 10may obtain the intelligence required to distinguish between ten andeleven digit dialing. This intelligence is conveyed in theabove-discussed connected NPA codes. Such codes identify all NPAs thatare connected to the NPA(s) juxtaposed with home system coverage area50. Moreover, remote programming session 42 may be performed as neededto track changes to connected relationships between NPAs. Such changesmay be implemented in a population of handsets 10 at minimal cost andinconvenience to subscribers.

Thus, remote programming session 42 allows handsets 10 to bemanufactured, inventoried, and distributed without any particulardistinction concerning where handsets 10 will eventually be authorizedfor use. When handsets 10 are sold, the activation process may lead tothe performance of remote programming session 42 so that handsets 10 maythen be compatible with at least a portion of the dialing rules ineffect for the handsets' home systems 50. Such programming may be laterchanged if the dialing rules change or if the user wishes to becomeactivated to operate on a different home system.

While FIG. 4 illustrates connected NPA1 as being adjacent to NPA2, thisis not the only arrangement. A connected NPA area, which may be reachedthrough ten digit dialing, may, in some locations, simply overlieportions of one or more other NPA area.

FIG. 6 shows a flow chart of an idle procedure 70 performed by handset10 to implement automatic dialing completion recognition. Generally,handset 10 performs procedure 70 when it is energized and is notinvolved in communicating with the cellular network. During idleprocedure 70 handset 10 waits for an incoming call or for a user toinitiate an outgoing call. As indicated by ellipsis in FIG. 6, idleprocedure 70 may perform many tasks that are not relevant to automaticdialing completion recognition. Such tasks may, for example, includeresponding to incoming calls and monitoring for and responding tochanges that may take place in service availability.

Procedure 70 performs a query task 72 to determine whether a user hasmanipulated a key, such as phone key 24 (see FIG. 1) of keypad 20, tosignal an off-hook condition. If not, program control remains in a loopwithin idle procedure 70. If the off-hook condition is detected, a querytask 74 determines whether service from the cellular network is stillavailable. If service is not now available, no outgoing call can bemade, and program control remains in a loop within idle procedure 70.

If task 74 determines that service is available, a task 76 clears adigit buffer, clears a first digit flag, resets a digit counter, andsets a “max digit” variable to a value of seven. The digit buffer, firstdigit flag, digit counter, and max digit items represent variablesmaintained in memory 38 (see FIG. 2). Clearing the digit buffer andresetting the digit counter initialize the digit buffer and digitcounter to indicate that no digits have been entered. Clearing the firstdigit flag indicates that a first digit is neither a zero nor a one. Themax digit variable is set to a default value of seven. If leftunchanged, the seventh dialed digit will be declared final digit 62 (seeFIG. 5), unless a user fails to enter digits faster than a minimum rate,which is preferably around one digit every four seconds. If four secondstranspires after a digit is entered without another digit being entered,an interdigit timer, discussed below, will declare the last-dialed digitto be final digit 62.

After task 76, a task 78 generates dial tone. Dial tone is generated byappropriately controlling DTMF tone generator 36 (see FIG. 2) togenerate an audio tone having a tonal quality that approximatesprecision dial tone. Preferably, DTMF tone generator 36 is instructed tosimultaneously generate 350 Hz and 440 Hz signals. In addition, receiver32 (see FIG. 2) is controlled to switch the DTMF tone generator audiooutput to speaker 14 (see FIG. 2).

Next, a query task 80 represents an entry point to a digit capture loop82. Task 80 determines whether any key from keypad 20 has been pressed.If no key has been pressed, a query task 84 determines whether aninterdigit timeout has occurred, but only after a first digit has beenentered. If no key press is detected and no interdigit timeout occurs,program control remains in digit capture loop 82 by returning to task80. Although not shown in FIG. 6, digit capture loop 82 may includeother tasks, such as continuing to check for service availability andtesting for a timeout duration, the expiration of which would cause anexit from loop 82 back to the top of idle procedure 70.

Generally, handset 10 uses two parallel processes to identify finaldigit 62 (see FIG. 5): a number analysis process and a timing process.Regardless of the process used to identify final digit 62, when finaldigit 62 is identified an origination message is sent to the cellularnetwork.

The default final digit 62 identification process is the timing process.The timing process will eventually detect final digit 62 for any dialedphone number. An interdigit timer is started or restarted for around afour second count each time a digit is entered, as discussed below. Whenthe interdigit timer expires, as determined at task 84, handset 10selects the timing process as the source for a decision regarding thecompletion of the dialing activity. At this point, program controlproceeds from task 84 to a task 86. Task 86 transmits the originationmessage to the cellular network. In the preferred embodiment, theorigination message conforms with standard cellular telephony formattingand protocol and informs the network of the called party's phone number.After task 86, handset 10 processes the call in a conventional manner,as indicated at task 88.

Thus, if the number analysis process fails to detect final digit 62 forany reason including an unusual dialing pattern, the origination messagewill eventually be transmitted after waiting the interdigit delayfollowing the last digit entered. This last digit may be the fourthdigit, for example, or the thirteenth digit as another example. However,the number analysis process quickly detects final digit 62 for the vastmajority of calls, and the waiting period that occurs following entry offinal digit 62 is avoided for the vast majority of calls.

When task 80 detects a key press, a query task 90 identifies whether thekey press corresponds to a numeric key or a non-numeric key. If anumeric key is entered, then a digit of a phone number is identified,and handset 10 proceeds to analyze the number collected thus far. If anumeric key is not entered, then handset 10 may perform conventionaltasks to respond to the key, as suggested by ellipsis in FIG. 6. Suchtasks may include terminating the digit capture process and returning tothe top of idle procedure 70 when an on-hook condition occurs.Additionally, redial or speed dial functions may be indicated.Eventually, a task 92 may be performed.

Task 92 responds to a non-numeric key which indicates a desire to deleteone or more previously entered digits. Such a key may, for example, be a“clear” key. In response to a delete request, task 92 removes one ormore digits from the digit buffer and appropriately adjusts the digitcounter. Next, a query task 94 determines whether the digit buffer isnow empty. So long as the digit buffer is not empty, program controlreturns to digit capture loop 82 to continue to capture digits. If thedigit buffer is empty as a result of task 92, program control returns tothe top of idle procedure 70. As a consequence of returning to the topof idle procedure 70, variables will be reinitialized and dial tone willbe restored so long as handset 10 is still off-hook and service is stillavailable.

When task 90 identifies the entry of a digit, a task 96 saves theidentity of the keyed digit in the digit buffer and increments the digitcounter. Next, a query task 98 determines whether the number analysisprocess has detected final digit 62. Task 98 makes its determination byevaluating whether the digit counter now equals the max digit variable.As discussed above, the max digit variable is initially set to a defaultvalue of seven to accommodate phone number format 64 (see FIG. 5), butit may change as the number analysis process analyzes the beginningdigits of the phone number. In applications where handset 10 is used inconnection with a PBX, the default may be set to four or five. Theprecise default value may be established through remote programmingsession 42 (see FIG. 3). If task 98 determines that the digit counterequals the max digit variable, then handset 10 selects the numberanalysis process to make the decision regarding when the dialingactivity is complete. As a result of this selection, program controlproceeds to task 86 to automatically transmit the origination message tothe cellular network. When task 98 determines that the digit counterdoes not equal the max digit variable, program control proceeds to anumber analysis process 100 to further analyze the digit.

FIG. 7 shows a flow chart of number analysis process 100. Process 100performs a query task 102 to determine if the identified digit is firstdigit 54 (see FIG. 5). Task 102 may examine the digit counter to makeits determination. If the identified digit is first digit 54, a task 103evaluates the first digit to determine if it represents an access code.Task 103 is an optional task that is included when handset 10 is used inconnection with a PBX system An access code may be a “9”, which maysignify an outside, and “8” which may signify a long distance line, andthe like. If an access code is detected, an appropriate response (notshown) may be to decrement the digit counter, controlling tone generatorto provide audible feedback, set the max digit default to 7, and returnprogram control to digit capture loop 82 (see FIG. 6). When dialingthrough a PBX, the access code is not passed to the cellular network andis not counted in detecting final digit 62.

After task 103, when a first digit is dialed task 104 preferablyremoves, but at least attenuates, the dial tone signal generated abovein connection with task 78 (see FIG. 6).

After task 104, a query task 106 determines whether first digit 54 is azero or a one. If the first digit is a zero or a one, then process 100of handset 10 may conclude that the phone number being entered does notfollow either of seven digit dialing format 64 or ten digit dialingformat 66 (see FIG. 5). However, process 100 cannot yet distinguishbetween eleven digit format 52 and indeterminate length format 68 (seeFIG. 5). Since the phone number might conform to eleven digit format 52,a task 108 sets the max digit variable to eleven. Since the phone numbermight also conform to indeterminate length format 68, task 108 sets thefirst digit flag to indicate that first digit 54 is either a zero or aone.

After task 108, a task 110 initiates the above-discussed interdigittimer to begin around a four second timeout. After task 110, programcontrol returns to digit capture loop 82 (see FIG. 6) to await the nextkey press. If no additional key press occurs before the interdigit timertimes out, handset 10 will select the timer process to provide thedecision regarding the completion of the dialing activity andautomatically transmit the origination message to the cellular network.

When task 102 determines that the last-entered digit was not first digit54, a query task 112 determines whether the last-entered digit wassecond digit 56 (see FIG. 5). When the last-entered digit was seconddigit 56, a query task 114 determines whether the first digit flag isset. The first digit flag gets set when first digit 54 is a zero or aone. If the first digit flag is not set at this point in the programflow, then the phone number cannot conform to indeterminate phone numberformat 68 (see FIG. 5), and program control proceeds to task 110 wherethe interdigit timer is again initiated for another four second count.

When task 114 determines that the first digit flag was set, a query task116 determines whether second digit 56 is a zero or a one. If seconddigit 56 is neither a zero nor a one, then the phone number cannotconform to indeterminate phone number format 68, and program controlproceeds to task 110 where the interdigit timer is reinitiated foranother four second count.

When first digit 54 is either a zero or a one and second digit 56 iseither a zero or a one, program control proceeds from task 116 to a task118. In this situation, indeterminate phone number format 68 has beendetected, and the number analysis process cannot reliably detect finaldigit 62 due to many variations which may occur in the digit streamlengths. Task 118 forces handset 10 to select the timer process toprovide the decision regarding the completion of the dialing activity.Task 118 forces handset 10 to select the timer process by disabling themax digit variable. This variable may be disabled, for example, bystoring a number or code therein which will prevent task 98 (see FIG. 6)from signifying that the digit counter equals the max digit variable.After task 118, program control proceeds to task 110 where theinterdigit timer is reinitated for another four second count.

When task 112 determines that the last-entered digit is not second digit56 (see FIG. 5), a query task 120 determines whether the last-entereddigit is third digit 58 (see FIG. 5). If third digit 58 is detected, atask 121 evaluates the first three digits to determine if a three digitformat number 63 (see FIG. 5) has been entered. Although not shown, if aformat 63 number such as 911 is entered, program control may proceeddirectly to task 86 to immediately transmit the origination message tothe cellular network.

After task 121 verifies that no format 63 number has been entered, aquery task 122 determines if handset 10 is currently roaming on acellular system other than its home system. If handset 10 is roaming,then program control proceeds to task 110 to restart the interdigitcounter and then collect additional digits. As discussed above, remoteprogramming session 42 (see FIG. 3) programs handset 10 to detect tendigit dialing format 66 (see FIG. 5) in connection with a geographicalarea where handset 10 is authorized for service. When handset 10 isroaming away from this area, the ten digit dialing recognitionprogramming may be invalid for the area where handset 10 is being used.Thus, handset 10 refrains from taking steps which can otherwise lead itto conclude that a phone number follows ten digit format 66 (see FIG.5). If a user is dialing a ten digit phone number, the timer processwill detect the completion of the dialing activity. However, if a useris roaming the number analysis process will still detect seven andeleven digit phone number formats 64 and 52, respectively.

When task 122 determines that handset 10 is not roaming, a query task124 determines whether the first three digits are listed in theconnected NPA list formed through remote programming session 42 (seeFIG. 3) and stored in memory 38 (see FIG. 2). If the first three digitsdo not describe a connected NPA, then ten digit dialing format 66 (seeFIG. 5) is not indicated, and program control proceeds to task 110 torestart the interdigit timer and then capture additional digits.

If the first three digits describe a connected NPA, then ten digitdialing format 66 is indicated and program control proceeds from task124 to a task 126. Task 126 sets the max digit variable to the value often. After task 126, program control proceeds to task 110 to restart theinterdigit timer and then capture additional digits. Handset 10 willinstantly and automatically transmit the origination message to thecellular network upon the entry of the tenth digit unless the user stopsdialing before entering the tenth digit, in which case the interdigittimer timeout will initiate the origination message.

As each additional digit is entered, program control again passesthrough number analysis process 100. For digits subsequent to thirddigit 58 (see FIG. 5), task 120 passes program control onto task 110 torestart the interdigit timer and then collect additional digits. The maxdigit variable remains at its default value of seven unless it was setto eleven above in task 108 in response to first digit 54, was entirelydisabled in task 118 in response to second digit 56, or was set to tenin task 126 in response to third digit 58 in connection with first digit54, second digit 56, and connected NPA programming.

In summary, the present invention provides an improved cellularradiotelephone that accommodates a call origination process whichapproximates the land-line call origination process. Dial tone isgenerated in response to an off-hook condition but is removed as soon asa first digit is dialed. For a vast majority of calls, a number analysisprocess immediately identifies a final phone number digit as soon as itis dialed, and an origination message is automatically transmitted tothe cellular network. For a few unusual calls where the number analysisprocess cannot reliably detect the final phone number digit, a timerprocess triggers transmission of the origination message after waitingfor an interdigit timeout duration of around four seconds. These fewunusual calls are not distinguished from the other calls but areidentified through giving the timing process a default status. Thepresent invention may be used in any location, may be manufactured,inventoried, and distributed without any particular area-of-usedistinction, and may yet perform a number analysis process which ispertinent only to a particular area. The present invention performsarea-specific ten digit phone number format detection in response toconnected NPA codes which are remotely programmed into theradiotelephone.

The present invention has been described above with reference topreferred embodiments. However, those skilled in the art will recognizethat changes and modifications may be made in these preferredembodiments without departing from the scope of the present invention.For example, while the present invention is described in connection witha particular cellular system, the present invention may be used inconnection with a wide variety of cellular systems and other radiotelecommunication systems where radio devices are used to dial phonenumbers. Furthermore, while the present invention has been described inconnection with a specific programming flow, those skilled in the artwill appreciate that a large amount of variation in configuring processtasks and in sequencing process tasks may be directed to accomplishingsubstantially the same functions as are described herein. These andother changes and modifications which are obvious to those skilled inthe art are intended to be included within the scope of the presentinvention.

What is claimed is:
 1. A method of operating a portable cellulartelephone to originate a call upon automatic recognition of phone numbercompletion, wherein the portable cellular telephone includes a case, adial tone generator within said case, and a keypad mounted to said case,and wherein said method comprises the steps of: generating an audibledial tone with the dial tone generator in response to an off-hookcondition; identifying, within the portable cellular telephone, theentry of earlier and later dialed digits via the keypad, said earlierdigit being a first digit of said phone number, and said earlier digitbeing dialed prior to said later digit and after initiation of saidgenerating step, said identifying step further identifying the entry ofa second dialed digit; determining, at the portable cellular telephonein response to a numeric value of said earlier digit, whether said laterdigit is a final digit of a phone number, said determining stepverifying that said second digit is neither a zero nor a one when saidfirst digit was a zero or a one; and automatically transmitting anorigination message from the portable cellular telephone when said laterdigit is said final digit of said phone number, said origination messageconveying said phone number to a telecommunication network.
 2. A methodas claimed in claim 1 additionally comprising the step of: detectingmanipulation of a key of the keypad which signals an off-hook condition;and wherein said generating step comprises generating, in response todetection of said off-hook condition, an audio tone at said portableradio telephone, said audio tone having a tonal quality approximatingprecision dial tone.
 3. A method as claimed in claim 2 additionallycomprising the step of attenuating said audio tone when said first digitis entered.
 4. A method as claimed in claim 3 additionally comprisingthe steps of: detecting manipulation of a key which signals aninstruction to delete one or more dialed digits; and generating saidaudio tone in response to said detecting step when said first digit isdeleted.
 5. A method as claimed in claim 1 wherein said identifying stepidentifies the entry of each digit of said phone number, including saidfirst, second, and later digits, and said method additionally comprisesthe steps of: initiating, when said second digit is a one or a zero andsaid first digit is a one or a zero, a wait period in response to theentry of at least one of said digits; and automatically transmittingsaid origination message when said wait period expires.
 6. A method asclaimed in claim 1 wherein said identifying step identifies the entry ofeach digit of said phone number, including said earlier and laterdigits, and said method additionally comprises the steps of: initiatinga wait period in response to the entry of at least one of said digits;and performing said transmitting step when said wait period expires. 7.A method as claimed in claim 6 wherein said initiating step isconfigured so that entry of each digit following said first digit ofsaid phone number reinitiates said wait period.